FDA approves stomach 'pacemaker'

By AP Medical Writer

WASHINGTON -- The government has approved a novel pacemaker-like device to zap the stomachs of a few thousand Americans a year who are at risk of literally starving to death from a mysterious stomach disorder.

Patients with severe gastroparesis cannot eat, sometimes even drink, because of continual nausea, vomiting and pain. Their stomachs do not churn properly to move food down the digestive tract. Until now, the sickest patients have survived only with feeding tubes inserted into the intestine or total intravenous nutrition.

"It's sad to think you could starve to death here in the United States because of a disease," said Jennifer Sivils, a 35-year-old mother of three so weak that her husband had to bathe her when her weight plummeted from 157 pounds to 98.

"I really thought I was going to die," the Arkadelphia, Ark., woman said Thursday, seven months after the implant allowed her to stomach some mild foods again. "I'm so grateful."

The Food and Drug Administration approved Medtronic Corp.'s Enterra implant to help patients like Sivils by zapping the stomach muscle with tiny electric shocks.

Enterra is not a cure. But in a small study many implant recipients dramatically improved, said Dan Schultz, FDA's director of abdominal devices.

The theory: The shocks stimulate nerves lining the stomach that control how it digests food, said University of Kansas gastroenterology chief Dr. Richard McCallum, who helped test the device.

It is the same rationale behind other neurostimulators that ease tremors by zapping a brain nerve, and ease incontinence by zapping a nerve that controls the bladder.

The Enterra theory is not proved, Schultz said. Enterra has been studied on so few people -- 33 -- that the FDA wonders if a placebo effect from simply having surgery could explain some of the benefit.

The 33 patients, who all failed gastroparesis medications, on average vomited 48 times a week before the implant. After surgery, vomiting episodes averaged 23 times a week when Enterra was turned on and 29 times a week when it was turned off. While patients felt better regardless, those similar numbers puzzled scientists.

Then the stimulator was turned on again for good, and some patients steadily improved. A year later, vomiting averaged 10 times a week. Some patients can eat fairly normally with little nausea while others had less benefit -- "a tremendous amount of variability," Schultz cautions.

Still, the effect seemed important enough that FDA approved Enterra last Friday under a special rule allowing "humane" treatments for rare, lifethreatening disorders to sell without extensive clinical trials. Medtronic disclosed the approval Thursday, saying the device is immediately available.

Actually, some 100,000 people may suffer gastroparesis. It is fairly common among diabetics. But in about a third of patients, like the Arkansas woman, it strikes otherwise healthy people for no apparent reason.

But in severe cases -- the FDA estimates fewer than 4,000 a year -- medication fails and patients cannot stomach any food.

Enterra is a battery-powered generator implanted in the abdomen with an electrode snaked up to the stomach muscle. It emits low-voltage shocks about once every six seconds. It is a $26,000 operation.

Getting Enterra to market was a battle -- an initial study was not promising and a skeptical Medtronic wanted to pull the plug, McCallum said.

But desperate patients begged to try Enterra. The FDA offered the special "humane treatment" review, and McCallum said Medtronic allowed him and University of Tennessee gastroenterologist Dr. Thomas Abell to complete the study.

Abell implanted Sivils' device last August. It took about a month before she noticed gradual improvement. She is not cured -- she still gets IV nutrition three days a week. But she has regained 22 pounds, eats vegetables and soups without vomiting for the first time in two years and can play with her children again.